A Mike Lynch-backed startup that uses machine-learning to detect hackers valued at $100 million in new funding

Mike Lynch, Founder and Chairman of Autonomy Corporation, poses for photographers at an awards ceremony in central London Thomson Reuters LONDON (Reuters) - Darktrace, a cyber-security firm backed by former Autonomy boss Mike Lynch, said it had raised $22.5 million from U.S.-based venture capital company Summit Partners in a funding round that valued the company at more than $100 million.

The investment comes just four months after the company raised $18 million to expand in Asia-Pacific, and Lynch said the additional funds were needed to fuel growth.

The company was one of Lynch's first investments after he left Hewlett-Packard Co in 2012 in an acrimonious split over the $11 billion acquisition of Autonomy.

HP is suing Lynch and a former colleague for more than $5 billion over their management of Autonomy. Lynch has said he would launch a counter claim.

Darktrace takes a different approach from other security software that seeks to police a boundary around networks.

Instead, he said Darktrace sits inside the network, and through machine learning recognizes abnormal activity and identifies malignant behavior, a process analogous to how the immune system works in the body.

"The business is growing exponentially," Lynch said.

The company, headquartered in Cambridge, England, and San Francisco, has seen it technology deployed in 104 companies, and it has partnered 63 other providers, such as BT for use in their own platforms.

Darktrace has not released figures, but it said its revenue was growing at more than 100 percent a year.

Lynch said there had been little progress in the HP cases. "It's moving at a speed that make a glacier look like it's been taking anabolic steroids," he said.